oil light coming on and off

[davo79]

My VS has the oil light come on when idling or when the car is driving and I take my foot off the accelerator or I brake. The light goes off when my foot is on the accelerator. Oil has been topped up and isn't leaking.

what going on?

[Bizmark]

Are you fully positive that there is enough oil in there?

Is the engine making any abnormal noises?

If not, it may just be a faulty oil pressure switch, if you recently pressure washed the engine bay that might have stuffed the switch up.

The light probably goes off, as when you get the revs up, oil pressure rises to some extent, so it raised the oil pressure above the threshold where the low oil pressure light comes on.

[davo79]

Yep sure oil is full. No ticking so I'm thinking not a oil pump. Only does it with low pressure so hoping it's not the bearings. I was thinking the pressure switch, but am concerned about cross threading if I do it myself.

[hako]

You won't have any problem cross threading the switch if you take your time and keep it lined up. Also when you slow down or brake, oil in the sump is forced to the front of the sump and may expose the pickup which then sucks air, but this would only be the case if the engine is low on oil. Another possible is a partially blocked oil pickup or the oil pressure relief valve blocked open.
To make sure I guess it's best to measure the oil pressure at idle... book says the oil pressure light comes on if pressure under 41Kpa so if it's above this figure at idle then it's the oil pressure switch that is faulty and if below then you will have to look elsewhere. Good Luck.

[jeepster]

I had similar problem. I replaced oil pressure switch, and it still came on at low revs (once engine was warmed up). The cause turned out to be the oil passageways were restricted by sludge - this
motor had over 250,000 km on it. Tried flushing with low-viscocity oil and diesel mix, which came out black after 15 minutes, but was not enough to fix problem. So I had to replace the engine.
I waited about 6 weeks for one with 100,000 km to turn up at wreckers yard.

[Andrew426]

Check it with an oil pressure guage and post back with results